1. Field of the Invention
This invention pertains mostly to a lithium metal anode and cell construction having suitable multi-layer protection for use in high pressure lithium-seawater or lithium-air semi-fuel cells, while providing a very high energy density.
2. Description of the Prior Art
Lithium-water and lithium-air primary batteries are the batteries of choice for various military applications, like unmanned underwater vehicles and unmanned air vehicles, due to their record high practical energy densities (1000 Wh/kg). However, the prior art underwater lithium batteries suffer from limitations of their use in relatively shallow depths, due to their low resistance to the high water pressure. Prior art lithium-air batteries do not utilize their full potential in energy density, due to their relatively heavy packaging structures. The prior art cell sizes are also limited by available ceramic layer, which can not be made in large sheets due to the brittleness of this material. Examples of the prior art batteries are described in U.S. Patents of Abraham et al. U.S. Pat. No. 5,510,209 and Visco et al. U.S. Pat. No. 6,432,584 B1. Therefore, it is desirable to provide a better protective structure of the cells and their anodes, which structures can withstand higher water pressure and also be very lightweight, and of a modular design.
The lithium anode and cell construction of the present invention does not suffer from prior art problems and provides many positive advantages.